The invention proceeds from a method of controlling an injection valve for an internal combustion engine in which the magnet coil of the injection valve is connected for a pulsating current by means of a semiconductor switch to an operating voltage in such a way that a current sufficient to open the injection valve flows during a first time interval, and that following this, there is possibly a second time interval, dependent on the stipulated duration of injection, providing a current which is sufficient for the holding open of the valve.
Injection valves for internal combustion engines with low electrical resistance are controlled by a so-called current control. In order to open the valve, one first of all waits, after connection, until the current through the magnet coil of the valve has reached a predetermined value. The current is then shut off and a pulsating voltage applied as a function of the intended duration of injection.
The rate of rise of the current during the first interval is however dependent on the value of the operating voltage and therefore, in particular, on the state of charge and any further load on the car battery. Thus, in the event of a low operating voltage it can take a rather long period of time before the predetermined peak value is reached. This dependence makes itself disturbingly felt in the case of electronically controlled fuel injection systems. Thus, for instance, in the case of low operating voltages, the first time interval may be so long that the injection of small quantities of fuel can no longer be precisely controlled.